Gelled amine rocket fuels

ABSTRACT

A gelled amine rocket fuel comprising hydrazine or derivatives thereof, cellulose acetate and hydroxyethylcellulose, for use in modern missile systems.

United States Patent Burdette et al. 1451 Mar. 21, 1972 54] GELLED AMINE ROCKET FUELS [56] References Cited [72] Inventors: George William Burdette; Dean Henry UNITED STATES PATENTS Chma Lake 3,116,187 12/1963 Scanlon et al. ..149/36 [73] Assignee: The United States of America as represented by the secretary of the Navy FOREIGN PATENTS OR APPLICATIONS [22] Filed: Oct. 18, 1965 978,105 12/1964 Great Britain ..149/36 [21 Appl. No.: 496,886 Primary ExaminerLeland A. Sebastian AttorneyG. J. Rubens, Roy Miller and V. C. Muller [52] U.S. Cl ..149/36, 149/18 '[57] ABSTRACT [51] Int. Cl. ..C06b 15/00 [58] Field of Search ..149/ 18, 36 A gelled mine oc et uel comprising hydrazine 0r derivatives thereof, cellulose acetate and hydroxyethylcellulose, for use in modern missile systems.

4 Claims, No Drawings GELLED AMINE ROCKET FUELS The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purpose without the payment of any royalties thereon or therefor.

The invention relates to improved gelled amine rocket fuels, and more particularly to gelled hydrazine, its derivatives, and mixtures thereof.

At present there is a dearth of fuel gels for liquid propellant rockets which are stable at temperatures as high as 74 C. Inorganic material such as silicon dioxide and carbon black have been used for gelling some liquid rocket fuels. Such materials as guar gum, gum arabic, gum tragacanth, Irish Moss extract, karaya gum, locust bean gum, methyl cellulose and sodium alginate have been used to gel hydrazine. The present invention "provides improved thixotropic or psuedoplastic amine fuels which are stable at high temperatures and exhibit no syneresis.

It is therefore an object of the present invention to provide a gelled rocket fuel which is simple and inexpensive to prepare and which maintains its chemical and physical properties after long periods of storage.

Another object is to provide a fuel with a gel structure which will hold particulate additives in uniform suspension throughout thereby preventing the clogging of orifices, valves, fuel lines, etc.

Yet another object is to provide a fuel which is safer to handle by personnel in a confined area such as on a ship.

A further object is to provide a rocket fuel which has a relatively high specific impulse and a relatively high density.

Other objects, features and many of the attendant advantages of this invention will become better understood by reference to the following description.

In accordance with the present invention the foregoing objects are accomplished by adding about 5 percent by weight of a cellulose ester and about 1 percent by weight hydroxyethylcellulose to hydrazine its derivatives, or mixtures thereof.

As preferred example, the following proportional mixture is given:

The cellulose acetate and hydroxyethylcellulose are mixed with continuous stirring into the hydrazine at ambient temperature. The cellulose acetate dissolves and later forms a precipitate which in combination with the viscous hydroxyethylcellulose forms a storable gel. Full gel strength is attained in about 24 hours. It is stable at 74 C. and exhibits no syneresis (gel shrinkage with exudation of liquid).

Further preferred examples include approximately the same amounts of cellulose acetate and hydroxyethylcellulose with unsymmetrical dimethylhydrazine, monomethyl hydrazine and mixtures thereof. Very small amount of water is present in the amine fuels used herein.

Another example consisted essentially of a mixture of 14 percent hydrazine and 86 percent methyl hydrazine to which cellulose acetate and hydroxyethylcellulose were added.

Other cellulose esters which can be used to gel the amine liquid fuels include cellulose butyra te, cellulose acetate butyrate, cellulose xanthate, cellulose triacetate and cellulose acetate hydrogen phthalate. Using cellulose esters without hydroxyethylcellulose results in gels which are unstable to high g forces and mechanical vibrations. Therefore, the use of hydroxyethylcellulose along with the cellulose esters is critical to this invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is: l. A gelled rocket fuel composition consisting essentially of a member selected from the group consisting of hydrazine, monomethylhydrazine, unsymmetrical dimethylhydrazine and mixtures thereof, about 5 percent by weight cellulose ester and about 1 percent by weight hydroxyethylcellulose.

2. A gelled rocket fuel composition consisting essentially of about 94 percent by weight hydrazine, about 5 percent by weight cellulose acetate and about 1 percent by weight hydroxyethylcellulose.

3. A gelled rocket fuel consisting of a mixture of hydrazine and monomethylhydrazine, about 5 percent by weight cellu lose acetate and about 1 percent by weight hydroxyethylcellulose.

4. The method for preparing gelled hydrazine comprising mixing together about 94 percent by weight hydrazine,

about 5 percent by weight cellulose acetate, and about l percent by weight hydroxyethylcellulose at ambient temperature until a smooth mixture results, and

curing for about 24 hours whereby a storable gel is formed. 

2. A gelled rocket fuel composition consisting essentially of about 94 percent by weight hydrazine, about 5 percent by weight cellulose acetate and about 1 percent by weight hydroxyethylcellulose.
 3. A gelled rocket fuel consisting of a mixture of hydrazine and monomethylhydrazine, about 5 percent by weight cellulose acetate and about 1 percent by weight hydroxyethylcellulose.
 4. The method for preparing gelled hydrazine comprising mixing together about 94 percent by weight hydrazine, about 5 percent by weight cellulose acetate, and about 1 percent by weight hydroxyethylcellulose at ambient temperature until a smooth mixture results, and curing for about 24 hours whereby a storable gel is formed. 